Doctors from four VA hospitals testified Tuesday before the House Veterans Affairs Committee that a "culture of retaliation" exists within the Department of Veterans Affairs that discourages employees from airing concerns about patient care, and discredits them when they come forward.

E-mails obtained by CBS News from a scheduler at the Los Angeles VA offer an example of the culture Head described. Jean Goode, a medical service assistant, wrote on April 11 to Dr. Robert Petzel - then the highest-ranking official at the Veterans Health Administration (VHA) - that a supervisor was manipulating the scheduling system "in order to improve our numbers." She wrote that she had first brought up her concerns about "inappropriate scheduling practices...in July or August of 2013" to her clinic manager. It is not clear what action, if any, was taken at that time.

Petzel, who retired a few months early amidst the furor over the wait-list scandal at the Phoenix VA, told Goode in an e-mail to "contact the medical center director, Donna Beiter." Goode complied.

A day later, Beiter wrote in an e-mail to her colleagues that she had not yet had a chance to determine whether they could "close the issue or do we need to do a bigger investigation etc." She then wrote of Goode: "She is an angry employee who did not get her performance award before they went on hold."

Though an e-mailed statement was provided to CBS News by Greater LA officials (read below), they declined to comment on this specific e-mail.

Goode's allegations of inappropriate scheduling practices were substantiated. In an e-mail between high-ranking VA health officials, one wrote: "...it looks like Jean Goode is right - there appears to be inappropriate actions by the supervisor." However, in an internal issue brief, a regional official wrote that there was "no intent by any staff member in the supervisor line to make GLA [Greater Los Angeles] access numbers look better."

An e-mail from Los Angeles regional official Skye McDougall to VA Central Office official Thomas Lynch, reads: "We will bring in staff outside the facility for more fact finding."

Jean Goode did not return calls for comment. In an e-mailed statement, Los Angeles VA officials wrote: "An OIG investigation into the matter began on May 30, 2014, and is still ongoing. We take allegations about employee misconduct very seriously and will continue to fully cooperate with the investigation."

According to an internal document obtained a month ago by CBS News, there were 999 new patients waiting more than 90 days to be seen by a doctor for the first time at the Greater Los Angeles VA healthcare system as of June 30.

At Tuesday night's hearing, U.S. Special Counsel Carolyn Lerner said her agency is investigating 67 retaliation complaints by VA workers in 28 states and 45 facilities.

Full statement by VA Greater Los Angeles Healthcare System:

At the Department of Veterans Affairs (VA), our most important mission is to make sure Veterans know that we are here to care for them and to provide the high quality care and benefits they have earned and deserve. VA Greater Los Angeles Healthcare System (VAGLAHS) is committed to timely access to care for our Veterans.

An OIG investigation into the matter began on May 30, 2014, and is still ongoing. We take allegations about employee misconduct very seriously and will continue to fully cooperate with the investigation.

As a proactive measure, we've provided refresher training to our VAGLAHS schedulers to ensure that they have a full understanding of VA's scheduling policy. We have and will continue to reinforce the importance of maintaining integrity as we manage patient access to care, and as Acting Secretary Gibson has said, we will continue our efforts in providing immediate, national reforms to accelerate access to care and restore trust among our Veterans. In addition to retraining staff, we have also established an additional management position to oversee all clerk supervisors and ensure competency with the scheduling system among clerical staff throughout VAGLAHS.

One of the fundamental responsibilities of leaders is to establish a workplace atmosphere in which employees are comfortable highlighting and sharing their successes--as well as identifying areas in which the organization can improve. Whether that means notifying managers and supervisors of isolated gaps or bringing attention to larger, systemic issues that impede excellence, it is important that all employees are encouraged to report deficiencies in care or services we provide to Veterans.